Searchlight elevating mechanism



Jan. s, 1935. l H, G,- FREN'CH 1,987,438

SEARCHLLIGHT ELEVATING MECHANISM l Filed Jup 23, 1953 HenT-'g G. FT' hoh, bg 1W 5M His Attorney.

Patented Jan. 8, 1935 y #Henry 'Frenchschenectady;

General Electric Company,

sniinonuenfr'iineyarmo MEcHANrsM NewYorkH 3 l Application ,I

N. Y., assignor to a corporation of e123, `193s,` serial No. 677,208!

Y c claims. (olg 24o-461.1% f

, My inventiony relates; "mechanicahcontrol device for searchlights, and more. particularly to anf improved elevating trollingv the movement a vertical plane Y e5 searchlight which is tatable ina horizontal plane.

The principal Vobj ect of mechanism for {con- `y' Ainvention is to provideY an improved;` elevatingfmechanism which will be unaffected by the and which rwill adjust the light without tending to rotation Vof the pedestal elevation of the Vsearchrotate the `pedestaljanfd thereby change the position `of the. searchlight in the `horizontal plane.

`For fa consideration of 'novel and my` inventijom the following specification thereto.

Figi of t e drawing illu tion, partially in section,

what I''believje jLto be attention is Adirected to and claims' appended strates ay front 'elevai of a searchlight provided with an elevating mechanism, builtin acf- `cordance with my invention, and Fig.' 2 an" en#- larged View of a portion ofthe elevatingwrnechanism.

, Figi *1. .df casing 1pi`vota11y mounted of a pedestalI 4 The searchlight may the drawing illstrats Semmigt onthe arms 2 and 3 bymeans of t'runnionsi5` and 6. be adjusted "for elevation in a vertical' plane by a worm'g'ear''attached shaft 9 and by aworm r3. `The worm between brackets` V10 attached to the l arm @heft sishrtatsmefm thefbrackets Y f The `loggia-.m1,e"isV rotatemy mounten, on a. sta;-

ltionary basei 12, being:

mounted on roller bearings 13 and 14,4:V Thenpedestalmay be'nrotatedby ashaft lf'mounted in a; bearing 16V located in a web 17 which is integralwith the `base 12.` 'The shaft 15 is providld with a is arranged 'to mesh with ra to the pedestal 4 'Any rotation of the shaft 15 thereforecausesa movement of the searchlight Vin a horizontal plane, Whichmovement is referred to for convenience/as the The movement traVeI'S e.

of the searchlight in a vertical plane, commonly referred to as the elevation, is

Vcontrolled by th'eshaftn, which in `turn is operated by a `drive shaft I`2Omountedon the base 12,

through'axcontrolrnechanism built in accordance with my invention. `"The, shaft 49 being mounted onthe pedestal lfzmoyes therewithQand thereby changes it's' loc ati onY .with A 'I'his movement resultsfin alrotationj of the shaft 9@ about its own y ;V Qn the-eser. had., i is.

respectto' shaft 20.

axisjif "ordinary gearing is used.

@time tif? leietsfihe Qf 2' Ymounted lona pedestal ro.-

' the vertical axis Ehousing and is rotated by gear 33 mounted yat the arms. YThe number of ance with my inventionI provlde an elevating ni'sm'inounted on lthe rotating pedestal 4 and gearednbetween the shafts 9a'nd 20 in such manner that it isindependent of or unaffected bythe rotation of thepedestal 4 and in turn exerts no rotating force upon Vthe pedestal. This vmechanism comprises two concentric vertical shafts 21 and 22 mounted 'coaxially with of rotation ofthe pedestal 4. lis mounted or'rotation in bearings 23 "and-,shaft'22 is mounted for rotation in Shaft21 is provided with a bevel gear 27 and shaft 22is provided with a similar gear 28 which gears are arranged to mesh with gearfs`29 andr30" attached to the shaft 20.V This shaft is mounted for rotation in bearing brackets V31 and 3,2 secured tothe stationary base 12. The ratios fo'f transmission of the gears 2'7-29l and 28-30 are eql'lfalito` eachjother so that the rotation of the two, vertical shafts in opposite dishare` @5.1.2.4. bearings 25 and 26.`

rections `from anyiixed point is exactly the same.

'meV shafts y21 and 22 are-'further provided, at their respective upper ends', withbeyel gears 33 Land" `34,`which two gearsare of equal diameter and equal number of teeth. The movement of these'gea'rs is transmittedto a differential mechanism"35,` Vwliich"in'tvurn is geared to a shaft 36. This part of the elevating mechanism maybe -refe'rredto for convenience as the base part of 'the-mechanism since it is attached to the base and'is therefore stationary.V n

YThedifferential-mechanism comprises a housing 37 to which the pinion spider 38is attached. The housing is mounted 'for rotation about the shaft36 in bearing 39',v located at one end of the a gear 40 meshing with n other end of the housing'. -The spider 38 is free to rotate about the shaft 36and carries pinions 41 on its respective the pinions 41 is immacase two are used being terial. In the present `meshed with planetary gearsl 42 and 43. The pinions 41 and the planetary gears 42 and 43 used in the 'present apparatus are of exactly the same diameter and have the same number of teeth, although thepinions 41Ymay be of any convenient size withresp'ect to the planetary gears. The gear 43 is attached to the horizontal shaft 36 and `the gearj42 Vis attached .to a collar 44 which is rotatable about the shaft 36 and whose outer "surface provides a bearing surface for the gear 40. A This arrangement provides a support for the mechanism including a differential gear mechathe centers of pressure for the two pairs of gears .Tfhis\ isf-, Avertical line 46 intersects the center lines;vqlffthel two pairs are vertically in line with each: other; clearly indicated in Fig. 2 wherein the of gear faces.

The horizontal shaft 36 is mounted for rotation in bearings 47 and 48..w.13earing 4.7: is: at-4 tached to a bracket 49 secured within the pedestal and is mounted so that the axis of the IJed'estalv intersects the center line of the shaft 36; With this` mountingf'the' gearsl 40 and 45 will'. always bein line with the ygears 33. and. 34 and. will. be held in mesh. by the bearing- 39 mounted in a bracket 50 which isgalso secured; to theped'estal. The horizontal'A shaftbearing 48 is. mounted in a bracket 51- which is provided with a housing 52v surrounding a pair `of bevel gearsi53. and 54 attached respectively to the shafts 9 and 36'. The shafts 36 vand-9, ,together with the. interconnecting gearing for driving the casing 1, may be referred to as the pedestal partr of the mechanism, this part of the mechanism being mounted directly on the pedestal and therefore movable therewithv relative4 tothe base partof the mechanism. The connection between, the two parts of the elevatingmechanism-isY-.cornpleted by the differentialWhichtransmits the force of the drive shaft to the casing in such manner that there `will be no tendency to rotate the pedestal and on the other hand when the. pedestal is rotated will continually charlgev theV position of` the'fpede'stal part of` thegmehanism relatively to the base'part sa that no movement ofthe casi-ngwill resultdue tothe rotation' ofthe pedestal.

. In operation; the shaft 15 isoperated, either by a motor or hand-wheel, torotate the searchlightv inV a horizontal plane. Whenthe pedestal v4 isso rotated the driving gears40 and'. 45 .for .the differential will roll along in-thesame direction on the gears 33 and 34.v There. can vvbe no 'movement' between the lgears 33 and 34l since these gears and their respective shafts are interlocked by the two pinions. 29 and30, which are both rigidly secured to the shaft 20 and are connected to the shafts 21 and 22 by gears 27 and 28, respectively. The gear 45 being onehalf the size of the-gear 40 will rotatetheplanetary 'car 42 twice as fastas the gear `40 will rotate the casing 37 and the spider.v 38. yBoth they pinions 41 and the planetary gear 42 are thereby rotated about shaft 36 and if rthe shaft 36A is to be maintained in a xed position, a certain relative motion between the casing gear 40 andthe driving gear 45 .for the` planetary gear. 42 must take place. With the planetary gears 42 and 43 interconnected with each other through Vthe pinions 41', it will be clear that the rotation` of the gear 45 will be necessarily the accumulativeV action of the rotation of the spider 38 about the shaft 36 and the rotation of the pinions 41 about the spider arms. This fact will be apparent if the spider 38 is considered stationaryand the two planetaryv gears 42 and 43 moved. Under transmitted by the pinions to the other in an opposite direction. The total movement of each with respect to. the spider will also be equal since each gear moves the same number of teeth. If then it is considered that gear 43 remains stationary, the spider 38 and the gear 42 will necessarily move and since the spider 38 will again be halfway between the stationary point on the gear 43and' the corresponding.; starting point on the gear 42, it will"l yhave rotated' one-half the dis- Atance that the gear 42 has rotated. The rotation of gear 45 is, therefore, twice that of gear 40.V Thisyis exactly.y the ratio that is established betweenA thesev twogears, as has been above explainedyandl therefore: the shaft 36 remains stationarywithrespectto the pedestal irrespective of the rotation-fof the pedestal with respect to the base: i I

When itvisdesired to adjust the elevation of vthe-searchlight, it is necessary to turn shaft 20 either byhalldor a motor. It has been pointed out above that thejtransmission ratios of the gears '27j-29' and; 28-30 are equall Itv has lalsoV been pointed'v outthat the application of'the torque from gearsv33lanj'd '34ito the gears 40 and 45 are directly ai'noveeac'h"othferand therefore at equal distances from theaxistofyrotation of the pedestal.y lurthermorev althoughthe gear ratios'. of the gears 33"-4'0v and.34-45 are..2 to 1, the actual force'applied, which is the product of torque and radius, are also equal since gear 40 is necessaiily, twice the radiusof gear 45. This arrangement therefore divid'es'the forces applied to the horizontal. shaft 36 for elevation adjustments, which tend to Arotate the pedestal', into two opposite horizontal'component's and balances them against each other through the differential mechanism. The elevation adjustments are tlrf'ereby made Without exerting a turningforce upon.the `pedestal and aifectingits position with respect. tothe` base. A

The transmission ofthe driving force of the gears 33"and 34 tothe gears 40 and/45, respectively, at equal distances from. the vertical axis ofrotati'on, as shown in Fig. 2, insures acom- A'pletebalancing of. the horizontal` components of the forcesr If,.how'ever,it is desired to exert a rotationalforce upon the pedestal simultaneously `witlfrtheadjustment of theelevation it. is only necessary to locate the twolpointsV of transmission at dierent distances from the axis. In that case, themmentsof the Atwohorizontal forces are unequal and therefore cannot'be balanced by the differential. since the ratio. of the gears must be maintained twoft'o one, as above explained. The elevation adjustment will not be changed in this latter case by the rotation ofthe pedestal, but

aj rotating force proportionate .to the'displa'ce- Yment of thetwo points with respect to each other isI obtained ywhen adjusting the elevation.

tion, the. same mechanism can be applied to the Vadjustment of gunsor any other object for which such adjustments are necessary.

What 1I` claimv as new and desire to. secure by ALetters Patent'lof the United States is:

. In a4 searchlight including a base, a pedestal mounted thereon for rotation about a verticalaxis `and a searchlight casing mounted on said pedestal for 'elevation in'a vertical plane, the' combination of an elevating mechanism including a drive shaftl mounted on' said base, a

`have used asearchlight to illustrate my inven- 'v of a mechanism forv moving pair of concentric shafts arranged coaxially with Qtal mounted for rotationthereon,` a searchlight casing mounted for elevationfon` said pedestal, the combination of a mechanism for controlling said elevation including a drive shaft mounted on said base, a pair of concentric shafts arranged coaxially with said pedestal and connected to said drive shaftfor rotation in opposite directions, and a differential mechanism mounted on said pedestal connected tosaid concentric shafts and said searchlight casing for elevating said drum independently of the rotation of said pedestal.

3. In a searchlight comprising a base, a pedestal rotatable with respect'to said base, and a searchlight casing movable in a vertical plane with respect to said pedestal, thel combination said` casing independently of the movement of said pedestal including a drive shaft mounted onsaid base, a

pair of concentric shafts mounted coaxially with said pedestal and connected to said drive shaft' for rotation in opposite directions, a `differential mechanism comprising a pair of planetary gears,

one of said gears being connected to said casing, the other being connected to oneof said concenf, tric shafts, a plurality of pinions interconnecting said gears, and a spider for supporting said pinions connected to` said -second concentric shaft. y

4. In a searchlight comprising a base,`a pedes` tal mounted for` rotation about a vertical axis on said base, a searchlight casing mounted on said pedestal for rotation about a horizontal axis, the combination of a drive shaftmounted on said base, a pair of concentric shafts connected to said drive shaft for movement in opposite directions and arranged coaxially with said pedestal, a differential mechanism connected to drive said casing and arranged to be driven by said concentric shafts, the points of transmission of force between said diierential and said shafts being arranged at equal distances from the axis of said pedestal.

5. In tal mounted on said base for rotation about a `vertical axis in a horizontal plane, a searchlight casing mounted on said pedestal for rotation in a vertical plane, ential mechanism mounted on said pedestal and arranged to drive said casing,

tween said drive shaft` and said diierential arranged to transmit the force of said drive shaft to said differential mechanism in two opposite and equal components, the points of sion of said components being at equal distances from the axis oi rotation of said pedestal.

6. In a searchlight including a stationary base, a pedestal mounted thereon and arranged to rotate about a vertical axis and a searchlight drum mounted for rotation about a horizontal axis on said pedestal, means formoving said searchlight casing relatively to saidV pedestal including a drive shaft mounted in said base, a pair of concentric shafts mounted coaxially with said pedestal and connected to said drive shaft for rotation.` in opposite directions at equal speeds, a differential mechanism mounted on said pedestal comprising a planetary gear connected to drive said searchlight drum, gear connected to one of said concentric shafts, pinions connecting said planetari7 gears, and a spider for supporting said `pinions connected to said second concentric shaft for rotation at onehalf the speed that said planetary gear rotates, the points of pressure applied by the gears of said concentric shafts to said gears of said differential being vertically in line with each other.

HENRY G. FRENCH.

a searchlight including a base, a pedesa drive shaft mounted on said base, and means connected bea` second planetary.

the combination of a differtransmis- 

